In the case that the interactions are controlled through the composition of the system (rather than temperature), the attractions that drive this phase separation can have a variety of sources, including the depletion interaction induced by non-absorbing polymers [1]}, [2]}, the attractions can come from bridging between colloidal particles [3]}, [4]} or through the critical Casimir effect [5]}, [6]}. Under the right conditions such attractions can lead to a network formed through spinodal decomposition, which undergoes arrest due to the asymmetry in viscosity of the two demixing phases, which is termed viscoelastic phase separation, or sometimes no attractions are actually needed to form such a network of fluids with very different viscosities [7]}. Whatever the origins of the emergence of the viscoelastic network, understanding colloidal gelation due to arrested spinodal decomposition is a long-standing challenge [2]}, [9]}, [10]}, [11]}, [12]}, [13]}, although the mechanism of solidification has been related to the emergence of rigid clusters, leading to a gel with viscoelastic mechanical properties [14]}, [15]}.
